It's almost impossible for any of us to drive a car or ride a motorbike in Ho Chi Minh City during rush hours, it looks like no traffic laws and the streets are so crowded with so many bicycles and motorbikes. The reason for almost no traffic accidents over there is the flow of traffic is so slow at around 3-5 MPH.
One of the video shows people just make left turn by cutting others, there are no left turn signal, actually some intersections have no traffic signal nor stop sign. It's just in jungle, who has bigger gut can go anywhere as he/she wants.